Scientists drill into major NZ fault line

A scientific expedition into a major fault line off the coast of New Zealand - capable of generating a magnitude 8 earthquake - has begun.

9 March 2018

Scientists have begun an expedition into New Zealand's largest fault line.

The Hikurangi subduction zone, where the Pacific plate slips under the Australian plate, is capable of generating a magnitude 8 earthquake.

An expedition team of international scientists will spend the next eight weeks drilling into the seafloor east of Gisborne to find out more about the plate boundary fault, GNS science said in a statement on Friday.

Expedition co-leader Dr Laura Wallace says the team will be taking samples of the seabed to understand how slow-slip earthquakes work.

"During a slow-slip event, it takes weeks to months for this fault movement to occur. This is very different from an earthquake, where fault movement occurs over a matter of seconds releasing energy suddenly."

Understanding the link between slow-slip events and earthquakes and tsunamis would allow better preparation particularly for coastal communities.

The investigation would involve two observatories being placed into the Australian tectonic plate above the area where slow-slip events occur, the first time these had been installed in New Zealand waters.

The Ministry of Civil Defence and Emergency Management has welcomed the expedition which would allow it to better prepare for a major earthquake or tsunami.

"As we learn more about the science we continue to refine our response and recovery plans."

"Understanding more about these zones and their ability to generate large tsunamis will allow for better risk modelling and hazard preparation for our coastal communities'', Civil Defence director Sarah Stuart-Black said.

The expedition is jointly led by scientists from GNS Science and Pennsylvania State University and is funded by the International Ocean Discovery Program (IODP) and the US National Science Foundation.